Counter‐transport between sugars and amino acids in rabbit ileum

Alvarado, Francisco; Torres-Pinedo, Ramón; Mateu, L.; Robinson, J. W. L.

doi:10.1016/0014-5793(70)80250-2

Cited by 17 publications

(2 citation statements)

References 14 publications

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“…Second, it has been impossible to detect valid countertransport effects between the two substrate groups, which are expected for molecules interacting with a common carrier [19,27]. Claims of countertransport have been reported [5,31], but in each case, competition for cellular energy reserves could not be ruled out as an alternative explanation. Third, and perhaps most significant, the interaction disappears in cells depleted of energy reserves by treatment with metabolic inhibitors [14,21].…”

Section: Discussionmentioning

confidence: 97%

Interaction between Na+-dependent transport systems for sugars and amino acids. Evidence against a role for the sodium gradient

Kimmich

Randles

1973

J. Membrain Biol.

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Summary. The concept that interaction between sodium-dependent transport systems represents competition for energy inherent in the transmembrane sodium gradient was examined with the use of isolated intestinal epithelial cells. The isolated cells exhibit transport interactions which are more significant in magnitude than those which have been described for intact tissue preparations. Accumulation of 1 mu valine is inhibited 60% by 10 mM 3-OMG. Conversely, uptake of 1 mM 3-OMG is inhibited only 20% by 10 mM valine. These data suggest that 3-OMG must discharge the cellular Na + gradient more effectively than valine, if Na + gradient dissipation can be taken as a basis for the inhibitory interaction. However, entry of 10 mu 3-OMG is significantly slower than the entry of 10 mM valine. Even if appropriate corrections are made for passive substrate entry and for differences in Na/substrate entry stoichiometry, it appears that valine should be somewhat more effective than 3-OMG in discharging the Na + gradient. In light of these facts, it seems unlikely that the mechanistic basis for interaction between sugar and amino acid transport systems can be related to concomitant co-entry of Na +. It is suggested that the interaction results instead from competition for energized intermediates generated at limited rates by basic energy transduction events associated with the cell membrane which serve in support of a variety of active transport systems.

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Section: Discussionmentioning

confidence: 97%

Interaction between Na+-dependent transport systems for sugars and amino acids. Evidence against a role for the sodium gradient

Kimmich

Randles

1973

J. Membrain Biol.

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“…Unfortunately, the conclusions of different investigators concerning the magnitude of unidirectional fluxes do not agree. Alvarado (1968) rind Alvarado et al ( 1970) reported that sugars decrease the irlflux of amino acids in rabbit and hamster srlaall intestine. On the other hand, Chez et ul.…”

Section: Discussionmentioning

confidence: 99%

The Role of Energy Metabolism in the Interaction between Amino Acid and Sugar Transport in the Small Intestine

Bihler¹,

Sawh²

1973

Can. J. Physiol. Pharmacol.

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Received September 5 , 1972 HIHL-LR, I., and SAWH, P. C. 1973. The role of energy nsetabolism in the interaction between amino acid and sugar transport in the small intestine. Can. J. The interaction between sugar and a~nlno acid transpor-t was studied in everted sacs of rat jejulauln in vitro. The addition of the actively transported nonmetabolized sugars, mgalactose and (1-methyl-uglucoside, to the mucosal medium inhibited the active transport of cycloleucine (1-amino-cyclopentane-I-carboxylic acid). This effect was largely counteracted by the simultaneous presence of D-glucose in the serosal medium or of n-fructose. The results indicate that provision of substrates for energy metabolism relieves the inhibition of transport and supports the hypothesis that the interaction between the intestinal transport of sugar and of amino acid is at least in part due to competition for a limited supply of metabolic energy. BIHLER, I., et SAWH, P. @. 1973. The role of energy metabolism in the interaction between anaino acid and sugar transport in the small intestine. Can. J. Fhysiol. Fharrnacol. 51, 378-382.L'interaction entre le transport des sucres et des acides arnines est etudieein v i~r o dans des sacs renversks de jejunum de rats. Lorsque le D-galactose et I'a-methyl-u-glucoside, sucres transportes activenlent mais non rnetabolises, sont ajoutes du c6tC mucosal, le transport actif de la cyclcucine (acidc 1amino-cyclopentane-1-carboxylique) est inhibe. Cet effet est lnrgement antagonise en la prisence simultanie dai Q-glucose dans le medium sereux, ou du n-fructose. Ces resailtats indiquent qiie I'apport des substrats energetiques soulage I'inhibition du transport et sont a l'appui de l'hypothcse selon laquelle B' interaction ciu transpor-t intestinal des sucres et des acides aminis est due, au moins en partie, a la cornpetition d9utilisation de 1'Cnergie metabolique disponible.Can. J. Physiol. Pharmacol. Downloaded from www.nrcresearchpress.com by San Francisco (UCSF) on 01/02/15For personal use only.

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Interaction between the sugar and amino-acid transport systems at the small intestinal brush border: A comparative study

Robinson

Alvarado

1971

Pflugers Arch.

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Counter‐transport between sugars and amino acids in rabbit ileum

Cited by 17 publications

References 14 publications

Interaction between Na+-dependent transport systems for sugars and amino acids. Evidence against a role for the sodium gradient

Interaction between Na+-dependent transport systems for sugars and amino acids. Evidence against a role for the sodium gradient

The Role of Energy Metabolism in the Interaction between Amino Acid and Sugar Transport in the Small Intestine

Interaction between the sugar and amino-acid transport systems at the small intestinal brush border: A comparative study

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